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authorMaciej Żenczykowski <maze@google.com>2021-07-01 04:48:34 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-07-21 10:04:19 +0200
commit8ae01239609b29ec2eff55967c8e0fe3650cfa09 (patch)
tree952bb6ba4b5bae52c3710dc5b6d32c2d05e26b74 /drivers/usb/gadget/function
parent6607d1a4c3c946d3420d33d1b561d7bee8f693c9 (diff)
usb: gadget: u_ether: fix a potential null pointer dereference
f_ncm tx timeout can call us with null skb to flush a pending frame. In this case skb is NULL to begin with but ceases to be null after dev->wrap() completes. In such a case in->maxpacket will be read, even though we've failed to check that 'in' is not NULL. Though I've never observed this fail in practice, however the 'flush operation' simply does not make sense with a null usb IN endpoint - there's nowhere to flush to... (note that we're the gadget/device, and IN is from the point of view of the host, so here IN actually means outbound...) Cc: Brooke Basile <brookebasile@gmail.com> Cc: "Bryan O'Donoghue" <bryan.odonoghue@linaro.org> Cc: Felipe Balbi <balbi@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Lorenzo Colitti <lorenzo@google.com> Signed-off-by: Maciej Żenczykowski <maze@google.com> Link: https://lore.kernel.org/r/20210701114834.884597-6-zenczykowski@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/gadget/function')
-rw-r--r--drivers/usb/gadget/function/u_ether.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c
index d1d044d9f859..85a3f6d4b5af 100644
--- a/drivers/usb/gadget/function/u_ether.c
+++ b/drivers/usb/gadget/function/u_ether.c
@@ -492,8 +492,9 @@ static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
}
spin_unlock_irqrestore(&dev->lock, flags);
- if (skb && !in) {
- dev_kfree_skb_any(skb);
+ if (!in) {
+ if (skb)
+ dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}